send_email · Run402 MCP: Risk & Policy

WHAT IT DOES

What send_email does on Run402

AI agents use send_email to create or update resources in Run402 — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Run402 environment.

WHY IT NEEDS A POLICY

Why send_email needs a policy

This tool creates new email messages and delivers them to recipients, which is a reversible write operation. Severity is medium rather than high because: (1) emails are typically recoverable/undoable via administrative actions, (2) single-recipient limitation reduces blast radius compared to mass mailing, (3) no financial transactions or destructive data operations occur.

From the tool's definition Tool performs 'Send an email' action which modifies state by creating and delivering a message. Description explicitly states ability to send emails with customizable templates or raw HTML content to a single recipient.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

send_email Rate-limited

send_email stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "send_email": {
      "limits": [
        {
          "counter": "send_email_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Run402, so you can run agents against it safely.

FAQ

Questions about send_email

What does the send_email tool do? +

Send an email. Two modes: template (project_invite, magic_link, notification) or raw HTML (subject + html). Optional from_name for display name. Single recipient only. Pass mailbox to target a slug/id; otherwise the configured default_outbound_mailbox_id is used. Result echoes mailbox_id and from_address when the gateway provides them. It is categorised as a Write tool in the Run402 MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on send_email? +

Register the Run402 MCP server in PolicyLayer and add a rule for send_email: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Run402. Nothing to install.

What risk level is send_email? +

send_email is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit send_email? +

Yes. Add a rate_limit block to the send_email rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block send_email completely? +

Set action: deny in the PolicyLayer policy for send_email. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides send_email? +

send_email is provided by the Run402 MCP server (kychee-com/run402). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.